Infant child restraint systems are well known in the art. Typically, the infant child restraint system is made up of two parts; an infant car seat and a base into which the infant car seat is mounted. Typically, the base is positioned on the seat of a vehicle, such as a car, truck, train or airplane, and secured using the restraint system of the vehicle, or a latch system. For example, a base is typically secured in place on an automobile seat through the use of the vehicle's seat belt or a latch system.
The infant car seat is then attached to the base, typically using one or more connection points. This allows the base to be left secured to the vehicle seat, while only the baby seat is removed. To provide maximum protection to the infant, the infant seat is typically oriented such that the infant's feet are nearest the seat back.
There are a number of issues associated with each of these two components. For example, as stated above, the base is typically secured to the vehicle seat via the restraint system. Typically, the restraint system consists of a lap belt, which is a horizontally disposed belt that passes across the passenger at the waist. The restraint system also includes a shoulder belt, which typically is slanted and positioned from the waist of the passenger on one side to the opposite shoulder. Alternatively, a latch system can be employed.
The base must be secured using typically the lap and shoulder belt. Given the single axis of restraint, it is important that the weight of the base (with the baby seat) is properly distributed. If the belt crosses the base at an unstable position, it is possible that the base may be able to rotate about this axis of restraint, especially in the case of a sudden change in motion, such as sudden braking or crash impact.
In the event of a sudden deceleration or crash impact, it is essential to protect the baby secured in the car seat. Typically, this is done by providing a hard exterior shell, and a second layer inside the shell, made with a material designed to absorb the compression forces during an impact. In many embodiments, this material is a polymer, such as expanded polystyrene (EPS), expanded polypropylene (EPP) or another impact absorbing material. Closest to the infant is a softer pad. To protect the infant in the event of a crash, it is important that the second layer be strong enough to absorb the compression forces. However, if the impact absorbing material is too hard, the force of impact will be transferred to the infant and specifically the spine and head regions. In addition, car seats accommodate infants of various sizes, from less than 10 pounds to those exceeding 25 pounds.
Obviously, the amount of force generated by a 10 pound infant is very different than that created by a 25 pound infant. In addition, the strength of an infant's bones and muscles varies with the size and age of the infant. In other words, a newborn cannot withstand significant impact, while an older, heavier infant can withstand significantly more force. Thus, if the impact absorbing support layer is too stiff, the newborn infant may be injured during an impact. On the other hand, if the impact absorbing support layer is too soft, a heavier baby may not be adequately protected by the support.
It would be beneficial if the issues associated with protecting infants of various sizes and ages could be addressed in a safe, convenient and cost effective manner.